Question

An element 'X' belongs to 3rd period and group 17 of the periodic table. State its (i) electronic configuration, (ii) valency. Justify your answer with reasoning.(All India - 2012)

Answer 1

Answer:

(I) 2,8,7 is it's electionic configration

(II) valacy is 1

it has this electronic configration cause it has three shells and requires one electron to attain property of noble gasses

Answer 2

Answer:

element X is chlorine

(i) k, L ,M 2,8,7

ii) valency 1

Explanation:

chlorine belongs to group 17 and period 3

its atomic no. is 17 so it electronic configuration is 2,8,7 in KLM shells

valency 1 because it can take 1 more electron in its outermost shell